Constant stroke variable displacement pump



Dec 24. 1 68 w; F. BEHM 3,411,702;

CONSTANT STROKE VARIABLE DISPLACEMENT" PUMP J Filed p il 1966 v '3 sheets-sum 1 mil" Ill BY I ATTORNEYS INVENTOR! Dec. 24, 1968 w. F. BEHM 3,417,702

CONSTANT STROKE VARIABLE DISPLACEMENT PUMP Filed April 18, 1966 3 Sheets-Sheet 2 60 4'9 5 5 i\ 5- I 5/ 5; K34 2/ i i i L INVEXTOR. VV/LL/AM F 5614M 1 H ATTORJEYS BY I Dec. 24, 1968 w. F. BEHM CONSTANT STROKE VARIABLE DISPLACEMENT PUMP 5 Sheets-Sheet 3 Filed April 18, 1966 INVENTOR. VV/LL MM F BEA/M 02 I 1 U 7. Q? 0% E 2 7 By ATTORNEYS United States Patent 3,417,702 CONSTANT STROKE VARIABLE DISPLACEMENT PUMP William F. Behm, Cowlesville, N.Y., assignor to Houdaille Industries, Inc., Buffalo, N.Y., a corporation of Michigan Filed Apr. 18, 1966, Ser. No. 543,199 9 Claims. (Cl. 10337) ABSTRACT OF THE DISCLOSURE A constant stroke variable displacement pump has one or more pistons driven reciprocably in pumping strokes in a respective cylinder which is reciprocably adjustably mounted in a housing to vary the stroke by adjusting means acting between the cylinder and the housing. Releasable means comprising a clutch retain the cylinder against movement out of adjusted relation.

This invention relates to a new constant stroke variable displacement pump, and more particularly concerns novel means for varying the displacement of such a pump.

Heretofore there has been need for more positive and greater range of control in high pressure single stroke reciprocating pumps. Pumps of this type are valuable in force feed engine lubrication.

An important object of the present invention is to provide a novel constant stroke variable displacement pump having new means for adjustably varying pump displacement.

Another object of the invention is to provide a new constant stroke variable displacement pump having novel means for varying pump displacement by adjustment of the pump cylinder relative to the pump piston stroke,

A further object of the invention is to provide new, simple, eflicient and economical means for varying the displacement selectively in a constant stroke pump.

Still another object of the invention is to provide novel displacement controlling means in a constant stroke pump, utilizing the pump piston and the cylinder as adjustable valve means for the purpose.

A yet further object of the invention is to provide a new constant stroke variable displacement pump of rugged, compact, eflficient construction embodying a minimum number of relatively simple, easily and inexpensively produced parts, and which will afford long, wearfree, continuous and effective service.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a side elevational view of a pump unit embodying features of the invention;

FIGURE 2 is an enlarged vertical sectional elevational detail view taken substantially on the line IIII of FIGURE 1;

FIGURE 3 is a top plan view of the unit shown in FIGURE 1;

FIGURE 4 is an enlarged vertical sectional detail view taken substantially on the line IV-IV of FIGURE 2.;

FIGURE 5 is a fragmentary upwardly facing sectional plan view taken substantially on the line VV of FIGURE 4;

FIGURE 6 is a fragmentary vertical sectional view of the upper portion of a pump unit according to the present invention showing a modification; and

FIGURE 7 is a fragmentary vertical sectional view of of the lower portion of a pump unit embodying features ice of the invention and showing a modified pump stroking mechanism.

Although the present invention lends itself to single pump units, it is also ideally suited for battery arrangement of a plurality of coordinated similar units in which the economies accruing from common housing castings are attained. Such a unitized battery comprising a pair of pump units 10 has been chosen for illustration in FIGURES 1-5 as exemplary. For this purpose a hollow base casting 11 provides a joint crankcase having external attachment flange means 12 by which the structure is adapted to be secured in place on and in association with the apparatus with which the pumps are to be used. On its front, or other suitable location, the crankcase may be provided with a drain plug 13. In its front upper portion, the crankcase base has a lubricant filling and mechanism access opening closed by a removable plate 14 provided with a breather hole 15, for each crankcase section.

For convenient service as a force feed lubricating central monitoring or control for various apparatus, but especially useful for adjustable oil lubrication of gas engine compressors, the pump units 10 are desirably const-ructed with a unitized housing casting 17 provided with a base attachment flange 18 secured as by means of screws 19 in fixed, but removable relation onto the upper rear portion of the base 11 in closing relation over an upwardly opening pump well 20.

Within the housing 17 is provided a vertical cylinder bore 21 for each of the pump units 10 extending throughout the length of the housing and opening downwardly into the well 20 and upwardly through the top of the housing and slidably mounting a tubular pump cylinder 22 which is of a length to extend a substantial distance downwardly into the well 20 and a limited distance upwardly above the housing. Reciprocably slidably operative within the cylinder 22 is a pumping plunger piston 23 having its lower end portion extending a suitable distance below the lower end of the cylinder and having fixedly and preferably integrally thereon a larger diameter shoulder terminal and follower 24.

Pumping reciprocations of the piston 23 are effected by means biasing the piston normally in one reciprocal direction and mechanical means driving the piston in opposition to the biasing means in the opposite reciprocal direction. For this purpose a strong helical compression spring 25 thrusts at its upper end against a spring retainer flange 27 engaged concentrically about the cylinder 22 within the well 20. At its lower end the spring thrusts under compression against a seating and retainer flange 28 shouldering against the shoulder follower 24. This biases the piston 23 downwardly in a protractional direction and maintains the follower 24 firmly against an antifriction roller 29 carried rotatably by the rear end portion of a rocker arm 30 intermediately pivoted on a rockershaft 31 which is mounted at its opposite ends in the side walls defining the crankcase chamber in the base 11. For stability and to shorten the free spans of the shaft 31 supporting the rocker arms 30 of both of the pump units, a vertical intermediate supporting web 32 is desirably provided within the crankcase as best seen in FIGS 2 and 5. On its opposite, and in this instance forward, end portion, the rocker arm 30 carries a second antifriction roller 33 which rides a suitable cam 34 on a camshaft 35 which is journalled through anti-friction bearings 37 mounted in the side Walls of the base 11. Closing the bearing openings in the side walls are closure discs 38 which are secured in place removably as by means of screws 39 and have respective retainer lug ears 40 overlapping the respective opposite ends of the rockershaft 31 to retain it against axial displacement.

Either or bot-h ends of the crankshaft may extend outwardly from the bearing retainer and shaft seal flanges 38 for keyed connection to power driving means of the apparatus or machine with which the pump assembly is used. Driving rotation of the shaft may be in either rotary direction and at any preferred speed within a range for which the assembly be rated taken into consideration size, pressure capacity, output pressure requirements, and the like. Pump stroke will remain constant at all speeds. Any preferred coordinated operation of the pump units 10 may be effected by relative lobe disposition of the driving earns 34, the relationship illustrated affording an alternaiing sequence in the respective pump strokes.

In each stroke cycle of the piston 23, its crown 41 moves in a pumping stroke toward and in a suction or recharging stroke away from the inner end of a stemlike cylinder head 42 which extends to a substantial distance inwardly from the top end of the bore of the cylinder 22, with a plurality of spaced sealing rings 43 preventing leakage past the stem. At a space height a suitable distance above the top of the housing 17, the cylinder head 42 is integrally joined to a larger diameter head extension 44 mounted fixedly in any suitable manner in a supporting yoke 45 secured to the housing as by means of bolts 47, with spacer sleeves 48 above the bolts maintaining a desired spaced relationship between the yoke and the top of the housing.

In each suction stroke of the piston 23, a liquid such as oil to be pumped is suitably supplied as through a duct-connecting nipple 49 secured into a counterbore 50 in the front of the housing 17. Thence the oil passes through one or more inlet openings 51 into an annular supply groove 52 in the bore 21 and a communicating annular groove 53 in the outer perimeter of the cylinder 22 from which a plurality of horizontally aligned radial ports 54 extend through the cylinder 22 to its pump bore. Location of the ports 54 is such that when a pumping shoulder 55 on the piston 23 uncovers the ports 54 during a suction stroke of the piston, a charge of liquid is drawn or pushed into the space between the crown 41 and the cylinder head 42. For high speed operation the fluid is desirably supplied under suitable pressure head. Air is prevented from being drawn into the groove 53 by respective upper and lower annular seals 56 in the cylinder perimeter. Although the crown 41 and the shoulder 55 may be one, they always coact even though spaced apart in the preferred arrangement shown wherein the shoulder 55 is separated from a piston head 57 by an annular elongated peripheral groove 58 in the piston and communicating through radial ports 59 with a longitudinal delivery bore 60 extending from these ports through the piston head crown 41.

During the pumping stroke of the piston 23, as the shoulder 55 passes and closes off the ports 54, the fluid trapped over the crown 41 is displaced toward the cylinder head stem 42 and through a longitudinal passage bore 61 therethrough extending from its inner end and continuing through the cylinder head body 44 wherein a counterbored enlargement provides a check valve seat 62. Fluid under pumping pressure is driven past a one-Way check valve 63 normally biased onto the valve seat 62 by means comprising a compression spring 64 maintained under compression by a spider 65 threaded into the enlarged passage in inward clearance relation to accommodate a coupling nipple 67 by which a suitable delivery conduit is connected to the discharge end of the delivery passage from the pump.

Inasmuch as the pump stroke is constant, displacement is adapted to be varied by changing the position of the supply ports 54 longitudinally along the stroke path of the pumping shoulder 55. To this end, the cylinder 22 is mounted to be selectively adjusted longitudinally in the bore 21 of the housing 17 for adjusting the position of the ports 54 anywhere within a range of from zero displacement to full displacement operation of the pump. For eifecting such adjustment in a smooth linear fashion, the upper end of the cylinder 22 is provided with an enlarged annular shoulder flange 6S seating on a complementary upward and outwardly facing annular shoulder 69 within an adjustment ring member 70 having an inside diameter to receive the flange 68 freely therein against the shoulder 69 and against which the cylinder flange is locked by a locking snap ring 71. Smooth, micrometer-like adjustments are effected through an externally threaded integral sleeve flange 72 extending from one side of the ring 70 about the cylinder 22 and threaded into a complementary counterbore 73 in the upper end of the cylinder bore 21 of the housing 17. The arrangement is such that when the ring 70 is threaded down against the top of the housing 17 full pumping displacement is attained. Reduced displacement is effected by turning the adjustment screw ring 70 to thread it up wardly and thereby raise the cylinder and shift the supply ports 54 upwardly for any desired degree of adjustment to the limit of zero displacement wherein the ring 70 is stopped by the yoke 45 and the ports 54 remain uncovered throughout the piston stroke, as indicated in dash outline in FIGURE 4, contrasted to the full displacement adjustment of the cylinder shown in full line. As will be apparent, the length of the peripheral groove 53 in the cylinder is such as to maintain full communication with the inlet passages 51 throughout the range of longitudinal adjustment of the cylinder.

Means are provided for maintaining the cylinder 22 firm against longitudinal looseness or backlash. Practical means for this is a split conical collet 74 having a cylindrical inner surface embracing the cylinder 22 and a tapered outer surface thrusting into a complementary downwardly flaring frustroconical cam surface 75 of a downwardly opening counterbore in the lower end portion of the cylinder bore 21. The collet 74 is of a length to project below the lower end of the housing 17 and has the spring retainer thrust flange 27 in upwardly thrusting engagement thereagainst under the strong bias of the spring 25. While the clutching engagement of the collet 74 is effective in preventing axial displacement of the cylinder 22 from any adjusted position under pumping action of the piston 23, the clutching action is adapted to be overcome by the superior force exerted by the adjusting screw ring 70.

While rotary adjustment movements of the ring 70 may be effected in various ways that afford suflicient leverage to overcome clutching resistance to longitudinal adjustment movement of the cylinder 22, a convenient, simple manual means for effecting adjustment comprises a capstan arrangement, wherein the ring has an annular series of spaced radially outwardly opening cylindrical sockets 77 into which the end portion of an adjusting lever rod 78 (FIG. 2) is adapted to be inserted to effect the desired degree of adjustment turning movement in either direction of the adjusting screw ring member.

In FIGURE 6 an arrangement of pump unit 10' is de picted in which the principal modification resides in supplying the liquid to be pumped through the cylinder head such that in each return or suction stroke of the piston 23' a charge of liquid is adapted to be drawn in through the cylinder head and then pumped into the delivery line during the pumping stroke of the piston. Variable displacement regulation is, similarly as in the form of FIGURE 4, effected by longitudinal adjustments of the cylinder 22' relative to the piston stroke, but in the reverse order, and utilizing the passage 50', 51' through the wall of the housing 17 as a regulation bleed-off leading back to the supply source or line. To this end, a combination cylinder head and yoke 79 is provided which has a depending cylinder head stem 80 projecting into the cylinder bore, the same as the cylinder head stem 42 of FIGURE 4 and provided with an annular series of peripheral seals 81 to avoid pumping leakage. An axial passage 82 through the stem 80 opens into the cylinder at its lower end and at its upper end communicates with a crossbore 83 which opens through opposite sides of the head 79 and is suitably counterbored to receive at one end a suitable connecting nipple 84 and at its opposite end suitable coupling means such as the nipple 67 shown in FIGURE 4 for attachment of a delivery conduit.

Suitable check valve means are provided in the crossbore 83 to cooperate with the piston in its pumping actions. Thus a one way check valve 85 is normally biased as by compression spring 87 into seating engagement with the inner end of the nipple 84 to permit drawing in of a charge of liquid past such check valve during the return or suction stroke of the piston. In the discharge or delivery portion of the crossbore 83, a one way check valve 88 is normally biased onto a seat 89 by means such as a compression spring 90 maintained under compression by a spider nut 91. Thus the valve 88 opens during pumping strokes of the piston and closes during the return or suction strokes while the valve 85 closes during pumping strokes and opens during suction strokes.

Longitudinal pump displacement adjustments of the cylinder 22 are adapted to be effected in the same manner as previously described, namely by substantially micrometer-like longitudinal movement of the cylinder relative to the piston 23 within the cylinder guide bore 21 of the housing 17', by turning of a regulating or adjustment ring screw 70'. While the adjusting screw 70' may be turned capstan fashion, it is also adapted to be gear driven, being for this purpose provided with peripheral gear teeth 92 engaged by a suitable complementary gear or rack member 93 having teeth 94 meshing with the gear teeth 92. Thereby adjustments may be effected automatically as part of a machine organization such as to effect coordinated variable demand requirements, and the like.

When the cylinder 22 is in its maximum protracted position relative to the upper end of the housing 17', as shown in full lines in FIGURE 6, with the head portion 79 serving as a limit stop, maximum pumping prevails because the ports 54 are continuously blocked from. communication with the pumping chamber within the cylinder above the pumping head and below the shoulder 55' which, in this instance is on the lower end of the head 57' above the ports 59 connecting the bore 60' with the groove 58. As the adjusting screw is run down into and toward the housing 17 to move the cylinder 22' in retractional direction, toward the dash line position shown, gradually decreased displacement of liquid is effected in the pumping strokes of the piston 23. Zero displacement is attained when the ports 54' are uncovered for communication with the pumping chamber during the entire stroke of the piston. Thus, there is continuous bleed-off to the supply or the liquid source and the pump idles.

It will be observed that in both of the forms of FIG- URES 4 and 6, it may be considered that the cylinder 22, 22' and the piston 23, 23' through the ports 54, 54' and the shoulder 55, 55 comprise an adjustable variable displacement regulating valve. Since this valve arrangement involves no moving operating parts other than the piston itself, it is trouble-free, positive and especially desirable due to its simplicity and efiieiency.

Where, for any reason, it is preferred to drive the pumping piston 23 directly instead of through a rocker arm, suitable modification in the .base 11 may be effected as shown in FIGURE 7; and a crankshaft 95 is mounted directly under the pump unit for direct engagement by the piston follower 24 with a suitable eccentric driving cam lobe 97 on the crankshaft.

It will be understood that variations and modifications may be effected without departing from the spirit and scope of the novel concepts of this invention.

I claim as my invention:

1. A constant stroke variable displacement pump of the character described comprising:

means providing a liquid supply and discharge system;

a hollow cylinder communicating with said system;

means for effecting longitudinal adjustments of the cylinder;

a piumping piston reciprocably mounted in said cylinmeans for driving the piston in a constant stroke cycle;

means on the cylinder and on the piston operative to regulate pump displacement in accordance with longitudinal adjustments of the cylinder;

and clutch means holding said cylinder against longitudinal displacement in the stroke cycle of said piston but permitting such displacement when effected by said means for effecting longitudinal adjustment.

2. pump according to claim 1, including a housing mounting said cylinder, a biasing spring about a portion of the cylinder, a spring retaining shoulder on the piston against which the spring thrusts, and said clutch means comprising a collet clutch against which the spring thrusts, said collet clutch gripping the cylinder frictionally.

3. In a constant stroke variable displacement pump of the character described comprising means providing a liquid supply and discharge system, a hollow cylinder communicating with said system, means for effecting longitudinal adjustments of the cylinder, a pumping piston reciprocably mounted in said cylinder, means for driving the piston in a constant stroke cycle, means on the cylinder and on the piston operative to regulate pump displacement in accordance with longitudinal adjustments of the cylinder, housing means defining a crankcase, a rocker arm in said crankcase having one end operatively engaging said follower, a rocker shaft extending through said crankcase and intermediately rock'ably mounting said arm, means journalling said rocker shaft with at least one end exposed to the outside of the housing means, a camshaft extending through said crankcase parallel to and spaced from said rocker shaft and having a cam drivingly engaging the opposite end of said rocker arm, bearing means mounted on said housing means and mounting said camshaft, the improvement comprising:

retaining flange means secured to said housing means in retaining relation to said bearing means and having a portion extending into confronting retaining relatron to said end of the rocker shaft.

4. In a constant stroke variable displacement pump comprising means providing a housing, a hollow cylinder reciprocably mounted in said housing, a pumping piston reciprocably mounted in said cylinder, means for driving the piston in a constant stroke cycle, the improvement comprising:

a head structure;

means mounting said head structure on said housing in substantial spaced relation to one end of said cylinder and providin substantial opening into said space between said head structure and said housing;

said housing and said head structure providing a liquid supply and discharge system operatively connected with said cylinder;

and a rotary screw member acting with said housing and said one end of the cylinder and having means accessible through said opening into said space for rotary adjustment to effect reciprocal adjustment of the cylinder relative to the piston.

5. A pump according to claim 4, in which said means for effecting adjustments of said rotary screw member comprise gear teeth on the screw member and means having complementary teeth meshing with the teeth on the screw member.

6. In a pump according to claim 4, said housing and said head structure providing spaced limit stops respectively engageable by said screw member to define respective opposite limits of reciprocal adjustment of the cylinder.

7. A pump according to claim 4 having means holding said cylinder against displacement in the operation of said piston but permitting reciprocal adjustment of the cylinder to be effected by said rotary screw member.

8. A constant stroke variable displacement pump comprising:

a housing;

a hollow cylinder reciprocably mounted in said hous- :a pumping piston reciprocably mounted in said cylinder;

means for driving the piston in a constant stroke cycle;

a head structure and means mounting the head structure on the housing in substantially spaced relation to one end of said cylinder and with a substantial opening into space between said head structure and housing affording access to said cylinder;

said housing and said head structure having a liquid supply and discharge system operatively connected with said cylinder for pumping by said piston in its reciprocations;

and means acting with said housing and said cylinder and having means accessible through said opening into said space for operating the same to effect reciprocal adjustment of the cylinder relative to the piston.

9. A pump according to claim 8, having means operative between the housing and the cylinder holding the cylinder against longitudinal displacement in the reciprocal operation of the piston but permitting such displacemerit for adjusting the cylinder relative to the housing and the piston when eitected by said means for effecting reciprocal adjustment of the cylinder.

References Cited UNITED STATES PATENTS 2,147,989 2/1939 Puurmann 74-53 2,223,759 12/1940 Dillstrom 103-2.1 3,099,217 7/1963 Bessiere 103--2.l 1,990,263 2/1935 Benedek 10337 2,041,422 5/1936 LOrange 103-37 2,337,510 12/1943 Trevaskis 10337 XR 2,371,054 3/1945 Le Clair 10337 2,439,879 4/1948 Allen 103-37 2,571,312 10/1951 Trevaskis 10337 2,821,926 2/1958 Miller et a1 10337 2,980,024 4/1961 Pope 10337 3,051,087 8/1962 Scholin 10337 XR 3,220,351 11/1965 Kling 103228 XR 3,229,640 1/1966 Williams 10337 FOREIGN PATENTS 280,961 12/1930 Italy.

DONLEY I. STOCKING, Primary Examiner.

T. R. HAMPSHIRE, Assistant Examiner.

US. Cl. X.R. 103-163 

